"Juan's always been a great technical fighter. He's perfected that and learned to control the combat zone," Beristain said. "He now knows how to handle left-handers."

Beristain embraced the fact that if Marquez had been able to avoid knockdowns -- three in their first bout (a draw) in 2004 and another in Pacquiao's split-decision triumph in 2008 -- the Mexican fighter has outboxed Pacquiao.

Beristain says Marquez can do it again as he flashes speed to complement a training camp dedicated to strength training.

"Obviously, Pacquiao has a great punch. Every minute of every round is danger," Beristrain said through an interpreter. "But no matter anyone says, we won that second fight. I'll go to my death saying that."

Beristain said he's spent dozens of hours reviewing replays of Pacquiao's fights since the March 2008 Pacquiao bout.

"You can lose a lot of sleep thinking how to beat Pacquiao," Beristain said. "That's what happens."

For Pacquiao, his training discipline is far superior to the way it was in 2008, when he struggled to make the 130-pound limit, then "ballooned to 149 [pounds] on fight day," according to Gary Poole book "PacMan," which was released in paperback this week.

Sipping from a holiday-red Starbucks cup Thursday morning, Pacquiao trainer Freddie Roach listed the improvements his fighter has made since that narrow escape in the second part of this trilogy.

"Manny's a compassionate guy and he's let the last couple of guys [Shane Mosley, Antonio Margarito] off the hook," Roach said. "Manny will never predict a knockout, but I know the way he's trained and prepared for this fight. I've seen how he's meaner to his sparring partners. He wants this fight badly. He has a fire in him."

Roach said Pacquiao is more adept at dealing with counter-punchers like Marquez now, and will deliver a well-schooled right hand the trainer calls "my baby."

Pacquiao unquestionably realizes the impact of this bout to his legacy and is geared to knock out Marquez early as he did in the third round of his third clash with former world champion Erik Morales in 2006.

Pacquiao has disdain for Marquez's inability to acknowledge defeat, but Roach said the hard feelings don't mean he's "going to fight a dumb fight."

The curious effect of Marquez's training with a strength and conditioning coach will be watched by Roach.

"I wouldn't have done that, but I credit [Marquez] -- he's got a plan, he's going for it," Roach said. "I'd want to go back to the counter-punching style that gave Manny problems in the first place. Muscle doesn't necessarily make you a better puncher. And too much muscle too quick can hurt you. I love the idea of him trying to exchange with us."

With 24 compelling rounds in the bank in this rivalry, Roach is respectful.

"They both get ready, get in shape and both come to fight," Roach said. "These are both very determined people. That's why we have a trilogy."